Tool retainer for percussive tools



Nov. 29, 1949 P. H. NAST TOOL RETAINER FOR PERCUSSIVE TOOLS Filed Jan. 8, 1948 PAUL H.NAST

IN VEN TOR.

ll-lmun I:

Patented Nov. 29, 1949 2,489,923 TOOL RETAINER FOR PERCUSSIVE TOOLS Paul H. Nast,

Worthington West Springfield, Mass., assignor to Pump and Machinery Corporation, Harrison, N. J a corporation of Delaware Application January 8, 1948, Serial No. 1,157

1 a This invention relates to percussive tools and, in particular, refers to an improved retainer'for drill steels, moil points, clay spades, chisels, etc.-

An object of this invention is to simplify the construction and operation of tool retainers for drill steels, moil points, clay spades, chisels, etc.

Another object is to eliminate positive fastening means, such as nuts or cotter pins, which may be shaken loose from the retainer during operation of the percussive tool.

With these and other objects in view, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawings, showing a tool retainer for percussive tools of a preferred form embodying the invention, and the features forming the invention will be specifically pointed out in the claims.

In the drawings: a

Figure 1 is a longitudinaI section through the chuck end of the cylinder of a percussive tool and shows the improved retainer in position to hold a drill steel in the cylinder.

Figure 2 is a side elevation, taken from the right of Figure 1.

Figure 3 is a bottom view of the structure shown in Figure 1.

Figure 4 is a detail of the fulcrum pin.

Figure 5 is an end view of the pin shown in Figure 4.

Referring more particularly to the drawings, a moil point I is slidably mounted in a sleeve 2 carried by the cylinder 3 of the percussive tool (fragmentally shown). The moil point or other tool has the usual collar 4 which strikes the sleeve 2 to limit its insertion into the cylinder 3. The retainer mechanism 5 comprises a removable stop which is spaced from the sleeve 2 and adapted to engage the collar 4 to prevent the moil point or other tool I from falling out of the cylinder 3.

In order tosupport the retainer mechanism 5, the cylinder 3 is preferably provided with an elongated protuberance ID which is generally disposed so as to be parallel to the cylinder 3 and the moil point I. The protuberance I is bifurcated at its lower end to provide parallel legs II and I2. Its upper end has a bore I3 which, preferably, is slightly inclined inwardly toward the axis of the cylinder 3 and moil point I.

The retainer latch I is pivotally mounted between the legs II and I2. This is accomplished partly in section,

by means of a novel fulcrum pin H which extends 55 mounted in the bore I3 and has a 3 Claims. (Cl. 27919.1)

through a cylindrical hole It in the latch I5 and rests in suitable holes I8 in the legs II and I2. The pin IT has a flanged head I9 which has a fiat 20 on one side. As shown in Figure 2, the pin I1 is inserted in the legs so that the flanged head I9 bears against the outside of the leg II. This leg has a fiat locking surface 2| on the outside which is slightly spaced from the flat 20 but which engages it to prevent rotation of the pin I1 and to provide it with a substantially fixed rotary position which it always assumes when removed and replaced.

The central portion of the pin I1 is turned down or decreased in diameter to provide shoulders 23 which are spaced apart by a distance equal to or greater than the thickness of the latch I5. These shoulders are disposed with relation to the fiat 20 so that, when the pin is in locked rotary position with surface 2I, they will at least be in that half of the pin I! which faces the bore I3. The groove 23 is preferably of the same diameter as the hole It and, hence, has its axis ofiset. In assembly, spring pressure, applied by means to be hereinafter described, forces the latch I5 into the groove 23' between the shoulders 23 so that the edges of the hole I6 bear against these shoulders. It will be realized that when this occurs the pin I1 is locked in transverse position with respect to the latch pin I5 and legs II and I2. Thus, with respect to its own axis, the pin I'I cannot be rotated or moved axially when it is assembled with the latch I5 under spring pressure. This feature obviates the necessity for a nut or cotter pin to hold the pin I! in place and thus makes it possible to provide a more streamlined appearance. The pin I! may, of course, be eas ly removed by releasing spring pressure on latch I5 so that the latch may be withdrawn from groove 23' and the pin slipped out of holes I6 and [8.

The latch I5 has a stop face 25 at its inner end which, as shown in Figures 1 and 3, is adapted to engage and stop the collar 4 but permits movement of the moil point I. The latch I5 is recurved so that its outer end has an inside face 26 which abuts the protuberance II], when the latch is in closed position, to prevent further pivotal movement of the latch I5 in a direction which would swing the stop face 25 down and away from the moil point or other tool.

As already indicated, spring pressure acts on the latch I5 to hold it in closed position (full lines in Figure 1) and in the groove 23'. This pressure is provided by a lock pin 30 which is slidably compression spring 3| bearing upon it and upon the retainer cap 32 which is threaded into the top of the bore l3. When the pin 30 seats on a shallow flat 33 which is formed on the inner periphery of the latch i5, the latch I5 is yieldably held in closed position. It will be noted that because of the inward inclination of the bore l3 that the line of action of the pin 30 is between the moil point I and the axis of pin I! thus tending to bias the latch It to the closed position. If desired, a removable bushing 35 may be provided for bore l3 to take the Wear occasioned by sliding movement of the pin 3il. Bushings 3t and washers 31 may also be provided to take the wear of the pin I? and latch l5.

In order to open the latch I5, leverage is applied to the outer end 26 and the pin rides up out of the fiat 33 against the force of spring 3! to permit pivotal movement of the latch i 5 on pin I? to dotted line position A. In this position the stop face, 25 is adjacent the pin 30 as shown in Figure 1. The moil point I will then drop out of the cylinder 2.

What is claimed is.

1. In a tool retainer for a percussive tool the combination of a protuberance offset from the tool axis and having spaced longitudinal legs with coaxial holes therein, a retainer latch having a hole therein disposed between the legs, a pin mounted in the leg holes and extending through the latch hole, said pin having a groove of substantially the diameter of the latchhole in which the latch is seated, cooperating locking surfaces on the pin and a leg to prevent substantial rotation of the pin, and resilient means inclined toward the tool axis yieldably holding the latch in the groove.

2. In a tool retainer for a percussive tool the combination of an elongated protuberance ofiset from the total axis, a retainer latch having a hole therein, a pin mounted in the protuberance and extending through the hole to pivotally connect the latch to the protuberance, said pin having a groove in which the latch is seated, said protuberance having a bore with its axis inclined toward the tool axis and intersecting the outer surface of the latch at a point between the tool axis and the axis of the pin, a locking pin slidably mounted in the. bore, and resilient means yieldably forcing the locking pin against the outer surface of the latch to hold the latch in the groove.

3; In a tool retainer for a percussive tool the combination of an elongated protuberance ofiset from the tool axis and having spaced longitudinal legs with coaxial holes therein, a retainer latch having a hole therein disposed between the a pin mounted in the leg holes and extending through the latch hole, said pin having a groove of substantially the diameter of the latch hole in which the latch is seated, cooperating locking surfaces on the pin and a leg to prevent substantial rotation of. the pin, said protuberance having a bore with its axis inclined toward the tool axis and intersecting the outer surface of the latch at a point between the tool axis and the axis of the pin, a locking pin slidably mounted in the bore, and resilient means yieldably forcing the locking pin against the outer surface of the latch to hold the latch in the groove.

PAUL H. NAST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Curtis 

